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D J Hampson

Publications and source records attributed to D J Hampson.

At least 37 records · Page 2Linked to original sources
PubMed2001

Carriage of intestinal spirochaetes by humans: epidemiological data from Western Australia.

The purpose of this study was to investigate carriage of intestinal spirochaetes by selected population groups in Western Australia. Stool specimens from 293 rural patients with gastrointestinal disorders, and from 227 healthy migrants from developing countries were cultured. Spirochaete isolates were identified using PCR, and typed by pulsed field gel electrophoresis (PFGE). Brachyspira aalborgi was not isolated. Brachyspira pilosicoli was recovered from 15 rural patients, all Aboriginal. Prevalence was 9.9% in 151 Aboriginals and 0% in 142 non-Aboriginals. Carriage of B. pilosicoli amongst migrants was 10.6% (24/227). Carriage was significantly increased in Aboriginal children aged 2-5 years (P = 0.0027) and in migrant individuals from the Middle East and Africa (P = 0.0034). Carriage was significantly associated with detection of faecal protozoa in both Aboriginals (P = 0.0021) and migrants (P = 0.012). PFGE results indicated that the B. pilosicoli strains were genetically diverse.

Adolescent↗
PubMed2001

Brachyspira aalborgi infection in four Australian children.

AIM: The clinical presentation of four children and adolescents (two males and two females with a mean age of 12.4 years; range 9-16 years) with colorectal spirochetosis is discussed. RESULTS: Symptoms included persistent diarrhea (n = 2), rectal bleeding (n = 1) and abdominal pain (n = 2). In all patients, colorectal spirochetosis was an unanticipated finding on colonic histology, and the presence of spirochetes was confirmed by the use of electron microscopy. Spirochetes were identified as Brachyspira aalborgi by using PCR amplification of the bacterial 16S rRNA and nicotinamide adenine dinucleotide oxidase sequences in all four patients. No other enteric pathogens were found. CONCLUSIONS: Although all patients appeared to respond to antibiotic treatment, the clinical significance of B. aalborgi as a human pathogen requires further investigation.

Adolescent↗
PubMed2001

Increasing viscosity of the intestinal contents alters small intestinal structure and intestinal growth, and stimulates proliferation of enterotoxigenic Escherichia coli in newly-weaned pigs.

Sources of viscous soluble fibre, such as barley and oats, have often been included in the weaning diet of the pig to accelerate development of the large intestine. Inclusion of a non-fermentable, viscous compound, sodium carboxymethylcellulose (CMC), in a low-fibre weaning diet was tested to assess the influence of digesta viscosity on the gut in the absence of increased fermentation. Two CMC sources, of low and high viscosity, were added to cooked rice-based diet at 40 g/kg total diet. A third control rice diet did not contain any CMC. Diets were fed for 13 d following weaning at 3 weeks of age. Addition of CMC to the diet significantly increased the intestinal viscosity of digesta within the small (P<0.001) and large (P<0.05) intestine. No simple association was found between increases in intestinal viscosity and effects on intestinal morphology and whole-body growth. The average empty-body-weight gain and the small intestinal villus height increased with low-viscosity CMC, but decreased with the high-viscosity CMC group. The full large intestinal weight increased in all pigs fed CMC. Dietary CMC (both low- and high-viscosity) increased the percentage moisture of digesta and faeces, and was associated with increased faecal shedding of enterotoxigenic haemolytic Escherichia coli. Feed ingredients in weaning diets that excessively increase the viscosity of the intestinal digesta may be detrimental to pig health and production.

Animal Nutritional Physiological Phenomena↗
PubMed2001

Comparative prevalences of Brachyspira aalborgi and Brachyspira (Serpulina) pilosicoli as etiologic agents of histologically identified intestinal spirochetosis in Australia.

DNA from gastrointestinal biopsy specimens from 28 Australian patients with histologic evidence of intestinal spirochetosis (IS) was subjected to PCRs to amplify segments of the 16S rRNA and NADH oxidase genes of Brachyspira aalborgi and Brachyspira (Serpulina) pilosicoli. B. aalborgi was identified in specimens from 24 (85.7%) patients and B. pilosicoli in those from 4 (14.3%) patients (2 of whom were also positive for B. aalborgi). For two patients, no product was amplified. This study demonstrates that B. aalborgi is much more commonly involved in histologically identified IS in Australian patients than is B. pilosicoli. This is the first report of amplification of B. pilosicoli DNA from humans with IS.

Adolescent↗
PubMed2001

Human intestinal spirochetosis: Brachyspira aalborgi and/or Brachyspira pilosicoli?

Intestinal spirochetosis in humans (HIS) is a condition defined by the presence of a layer of spirochetes attached by one cell end to the colorectal epithelium. The pathologic significance of HIS is uncertain, but it has been linked to chronic diarrhea and other abdominal complaints. Two anaerobic intestinal spirochete species have been associated with HIS, namely Brachyspira pilosicoli and Brachyspira aalborgi. Brachyspira pilosicoli, which colonizes many animal species, is common (approximately 30%) in the feces of people from developing countries, including Australian Aborigines, and in HIV+ patients and male homosexuals in Western societies. It is also commonly seen attached to the rectal mucosa of homosexual males. In other groups in Western societies both the presence of B. pilosicoli in feces and histologic HIS are uncommon (approximately 1.5%). Brachyspira aalborgi is an extremely slow growing and fastidious spirochete, which previously had been isolated from an HIS patient in Denmark. Recent studies using polymerase chain reaction amplification of DNA from intestinal biopsies from a series of cases of HIS in the general Western population demonstrated that B. aalborgi, rather than B. pilosicoli, was the main spirochete species involved in these patients. This review outlines recent developments in the study of HIS and the two spirochete species, and identifies priorities for future research.

AIDS-Related Opportunistic Infections↗
PubMed2001

Serologic detection of Brachyspira (Serpulina) hyodysenteriae infections.

Swine dysentery (SD) caused by the intestinal spirochete Brachyspira hyodysenteriae is an economically important disease in pig-producing countries throughout the world. To date, no specific serologic assay is commercially available for the diagnosis of pigs with SD. Several serologic techniques have been identified in the past; however, these tests have all used either whole-cell proteins or lipopolysaccharide (LPS) as the antigen. Whole-cell antigens are plagued with false-positive reactions due to cross-reactivity with common proteins shared with other spirochetes. LPS antigens produce fewer false-positives; however, false-negatives may result due to LPS components being serogroup-specific. Generally, these techniques are useful for detecting infected herds, but are unreliable for the detection of individual infected pigs. In order to develop improved serologic tests it will be necessary to identify suitable diagnostic antigens, in particular immunogenic cell-surface structures which are specific to B. hyodysenteriae but common amongst different strains of the species. Recently, we identified and cloned a 30-kDa outer membrane lipoprotein (BmpB) which is specific to B. hyodysenteriae and is recognized by experimentally and naturally infected pigs. In this review we summarize the available serologic tests for SD, and speculate on the use of recombinant BmpB as an antigen for future development of an improved serologic test for SD diagnosis.

Agglutination Tests↗
PubMed2001

Intestinal spirochete infections of chickens: a review of disease associations, epidemiology and control.

This paper presents an overview of intestinal spirochete infections of chickens. It focuses particularly on studies in Australia, where recent surveys of 136 layer and broiler breeder flocks have revealed a high rate of infection (>40%) with intestinal spirochetes. Infection was not detected in broiler flocks. Approximately 50% of isolates from infected flocks were Brachyspira (Serpulina) intermedia or B. pilosicoli, with the other isolates being B. innocens, B. murdochii or the proposed species 'B. pulli'. No isolates of B. alvinipulli were found. Intestinal spirochetes were significantly associated with wet litter problems and/or reduced egg production. Experimental infection of point-of-lay birds with either B. intermedia or B. pilosicoli caused reduced egg production, and, with B. intermedia, a significant increase in fecal moisture content. Infection with B. innocens caused no significant changes. In-water treatment of a flock with a mixed spirochete infection using lincospectin resulted in a slimy diarrhea lasting for 2-3 weeks, followed by absence of spirochetes for 3 months. Birds treated with tiamulin remained healthy, and had a reduced level of infection with intestinal spirochetes (30%) for 3 months. Trials are under way to test the efficacy of antimicrobials in point-of-lay chickens experimentally infected with either B. intermedia or B. pilosicoli.

Animals↗
PubMed2000

Identification of the gene encoding BmpB, a 30 kDa outer envelope lipoprotein of Brachyspira (Serpulina) hyodysenteriae, and immunogenicity of recombinant BmpB in mice and pigs.

A gene encoding a 30kDa outer envelope protein of the intestinal spirochaete Brachyspira (Serpulina) hyodysenteriae, was cloned and expressed in Escherichia coli strain XLOLR. Five phagemids containing DNA inserts encoding the protein were established and one clone (pSHA) was sequenced. An 816bp hypothetical open reading frame (ORF) was identified, with a potential ribosome binding site (AGGAG), and putative -10 (TATAAT) and -35 (TTGAAA) promoter regions upstream from the ATG start of the ORF. A 12bp inverted repeat sequence, possibly serving as a transcription terminator, was identified downstream from the TAA stop codon. Analysis of the amino acid sequence identified a 19 residue hydrophobic signal peptide, incorporating a potential signal peptidase cleavage site and membrane lipoprotein lipid attachment site. Further analysis of the amino acid usage of this lipoprotein, designated BmpB, showed its possible outer membrane localisation. Comparison of the gene encoding the lipoprotein, bmpB, with GenBank nucleotide sequences showed that it has homology with the gene (plp3) encoding Plp3, an outer membrane lipoprotein of Pasteurella haemolytica (54% identity in 735bp). Comparison of the deduced amino acid sequence with the SWISS-PROT amino acid database revealed greatest homology with the outer membrane lipoproteins (Plp1, 2, 3) of P. haemolytica (34% identity in 242 aa, 37% identity in 250 aa, and 39% identity in 272 aa, respectively), and lipoproteins (rcsF and lipoprotein-28) of E. coli (40% identity in 267 aa and 36% identity in 263 aa, respectively). Three of the recombinant E. coli clones (pSHA, pSHD, and pSHE) were formalinised and used to immunise mice. A bacterin preparation of one recombinant E. coli clone (pSHA) was used to immunise pigs. Sera from these mice and pigs recognised the 30kDa lipoprotein in outer membrane preparations of B. hyodysenteriae, indicating the immunogenicity of recombinant BmpB. Sera from pigs naturally infected with B. hyodysenteriae also reacted with recombinant BmpB expressed in E. coli.

Amino Acid Sequence↗
PubMed2000

Influences of diet and vaccination on colonisation of pigs by the intestinal spirochaete Brachyspira (Serpulina) pilosicoli.

The purpose of this study was to determine whether methods used to control swine dysentery (SD), caused by the intestinal spirochaete Brachyspira (Serpulina) hyodysenteriae, would also be effective in controlling porcine intestinal spirochaetosis (PIS) caused by the related spirochaete Brachyspira (Serpulina) pilosicoli. Weaner pigs in Groups I (n=8) and II (n=6) received a standard weaner pig diet based on wheat and lupins, whilst Group III (n=6) received an experimental diet based on cooked white rice and animal protein. Pigs in Group II were vaccinated intramuscularly twice at a 3-week-interval with a formalinised bacterin made from B. pilosicoli porcine strain 95/1000 resuspended in Freund's incomplete adjuvant. Eleven days later pigs in all groups were infected orally with 10(10) cells of strain 95/1000 on three successive days. One control pig in Group I developed acute diarrhoea, and at post-mortem had a severe erosive colitis with end-on attachment of spirochaetes to the colonic epithelium. All other pigs developed transient mild diarrhoea and had moderate patchy colitis at post-mortem 3 weeks later. B. pilosicoli was isolated from the faeces of all pigs, except for one fed rice, and was isolated from the mesenteric nodes of three pigs from Group I and from one vaccinated pig in Group II. Consumption of the rice-based diet, but not vaccination, delayed and significantly (p<0.001) reduced the onset of faecal excretion of B. pilosicoli after experimental challenge. Vaccination induced a primary and secondary serological response to B. pilosicoli, as measured using sonicated whole cells of strain 95/1000 as an ELISA plate coating antigen. Antibody titres in the vaccinated pigs then declined, despite intestinal colonisation by B. pilosicoli. Both groups of unvaccinated animals also failed to develop a post-infection increase in circulating antibody titres.

Animal Feed↗
PubMed2000

Experimental models of porcine post-weaning colibacillosis and their relationship to post-weaning diarrhoea and digestive disorders as encountered in the field.

The aim of this study was to develop a reliable model system of porcine post-weaning colibacillosis, and in doing so to assess the primary relationship of enterotoxigenic Escherichia coli to post-weaning diarrhoea and digestive disorders as encountered in the field. Six sequential experiments were carried out using 168 SPF piglets weaned into an optimal controlled environment at 28 days of age. The piglets were allocated to 23 treatment groups, 17 of which were inoculated either orally or intragastrically with enterotoxigenic strains of E. coli (LT+, STI+, STII+) possessing adhesive factors including K88 (F4). The piglets were challenged either once (Day 4 post-weaning) or on several days post-weaning, with the challenge load for each inoculation varying from 10(8) to 10(12) CFU. Overall 14.5% of inoculated pigs developed severe illness and died: these had lesions in their digestive tracts typical of colibacillosis. Diarrhoea occurred on at least 1 day in 50% of inoculated pigs, but was transient (1.7 days on average), appeared very soon after challenge (sometimes within half a day), and was accompanied by signs of depression and low weight gain. Generally a prompt recovery then occurred. In the second 2 weeks post-inoculation daily weight gain reached the same level in most inoculated groups of pigs as in the uninoculated controls. Only a small number of pigs developed a chronic enteritis lasting several days, as is typically observed in field cases. Diarrhoea was more common in the piglets that were tested adhesive positive to the K88 fimbriae receptor, but the disorders were no more severe in these animals. The response of all pigs depended primarily on the inoculum used, and especially on the challenge load. Although enterotoxigenic E. coli are clearly important in the aetiology of post-weaning diarrhoea, other factors are also required for the production of the chronic post-weaning digestive disorders and ill-thrift that are commonly encountered in commercial piggeries.

Animals↗
PubMed2000

Evaluation of a 23S rDNA polymerase chain reaction assay for identification of Serpulina intermedia, and strain typing using pulsed-field gel electrophoresis.

A polymerase chain reaction assay, amplifying a 1027 base pair portion of the 23S rDNA gene, was evaluated for identification of the intestinal spirochaete Serpulina intermedia. A total of 34 strains of S. intermedia isolated from pigs and chickens and 195 strains of other related species were tested. The optimised assay correctly identified all the S. intermedia strains, but generated 11 false positive reactions, giving a test sensitivity of 100% and a test specificity of 94.3%. The false positive reactions were generated from strains of four different species of intestinal spirochaetes, and the product was of the original predicted size. This suggests that the primer sites selected on the 23S rRNA gene were not completely specific for S. intermedia. Pulsed-field gel electrophoresis was then developed to investigate diversity amongst the S. intermedia strains. All strains tested had distinct DNA banding patterns using Mlu1, although three isolates from chickens on the same farm appeared closely related. The collection exhibited considerable genetic diversity, and strains from pigs and chickens were distributed in clusters throughout the dendrogram produced. The most closely related porcine and avian strains shared only 62% similarity.

Animals↗
PubMed2000

Extrusion of wheat or sorghum and/or addition of exogenous enzymes to pig diets influences the large intestinal microbiota but does not prevent development of swine dysentery following experimental challenge.

A study was made of dietary influences on the large intestinal microbiota of pigs and on the incidence of swine dysentery (SD) after experimental infection with Brachyspira hyodysenteriae, the aetiological agent of SD. Animals were fed diets based either on wheat (expts 1 and 2) or sorghum (expt 2). Grains were ground and fed either raw or after high temperature and pressure extrusion and/or after addition of exogenous enzymes to the whole diet to reduce the starch and soluble non-starch polysaccharides available for fermentation in the large intestine. Limiting fermentation creates conditions that apparently reduce the incidence of SD after infection with B. hyodysenteriae. The diets were fed to weaned pigs for 4-6 weeks, then half the animals on each diet were killed and gut samples collected for microbiology. The treatments had little effect on bacterial numbers. In expt 1, dietary extrusion of wheat reduced lactobacilli in the large intestine. Addition of enzymes to extruded wheat-based diets in expt 2 reduced facultative anaerobes and increased non-sporing anaerobes. Addition of enzymes to a raw sorghum diet in expt 3 decreased numbers of facultative anaerobes, while extrusion of sorghum increased total anaerobes. Bacteroides spp. and Fusobacterium spp., which act in synergy with B. hyodysenteriae in SD, were isolated at a higher percentage in pigs fed the untreated wheat diet than in pigs fed the treated wheat diets. Following experimental infection the incidence of SD amongst pigs fed treated wheat diets was slightly lower than those fed the untreated diet, but with sorghum-based diets the opposite was found. Overall, the different dietary treatments used did not significantly reduce SD.

Animals↗
PubMed2000

Evaluation of a novel antimicrobial polymer for the control of porcine postweaning colibacillosis.

OBJECTIVE: To determine whether CHEMYDERTM polymer has potential for use in the control of porcine postweaning colibacillosis (PWC). PROCEDURE: Two experiments were conducted in which 50 young pigs, either receiving CHEMYDERTM polymer in their food or not, were challenged orally with cultures of beta-haemolytic Escherichia coli immediately after weaning. Their response in terms of development of diarrhoea, and the extent of colonisation of the intestinal tract by the bacteria was monitored. In a third experiment CHEMYDERTM polymer was added to the water supply of a group of 15 pigs on a piggery where PWC was an ongoing clinical problem. The response of these pigs was compared with that of pigs vaccinated against PWC or left unmedicated. RESULTS: In both experimental infection trials the pigs receiving CHEMYDERTM polymer showed significantly reduced intestinal colonisation with the challenge strain of E coli, and, in trial 2, significantly less diarrhoea after weaning compared to pigs not receiving CHEMYDERTM polymer. In the field trial the pigs receiving CHEMYDERTM polymer had significantly less diarrhoea and required significantly less antibiotic treatment than the other two groups of pigs. CONCLUSION: CHEMYDERTM polymer has potential for use in the control of PWC.

Acrolein↗
PubMed1999

Differentiation of Serpulina species by NADH oxidase gene (nox) sequence comparisons and nox-based polymerase chain reaction tests.

The NADH oxidase genes (nox) of 18 strains of intestinal spirochaetes were partially sequenced over 1246 bases. Strains examined included 17 representatives from six species of the genus Serpulina, and the type strain 513A(T) of the human intestinal spirochaete Brachyspira aalborgi. Sequences were aligned and used to investigate phylogenetic relationships between the organisms. Nox sequence identities between strains within the genus Serpulina were within the range 86.3-100%, whilst the nox gene of B. aalborgi shared between 78.8-83.0% sequence identity with the nox sequences of the various Serpulina strains. A phenogram produced based on sequence dissimilarities was in good agreement with the current classification of species in the genus Serpulina, although an atypical strongly beta-haemolytic porcine strain (P280/1), previously thought to be S. innocens, appeared distinct from other members of this species. Primer pairs were developed from the nox sequence alignments for use in polymerase chain reaction (PCR) identification of the pathogenic species S. hyodysenteriae (NOX1), S. intermedia (NOX2), and S. pilosicoli (NOX3), and for the combined non-pathogenic species S. innocens and S. murdochii (NOX4). The PCRs were optimised using 80 strains representing all currently described species in the genus Serpulina, as well as the type strain of B. aalborgi. Tests NOX1 and NOX4 specifically amplified DNA from all members of their respective target species, whilst tests NOX2 and NOX3 were less sensitive. NOX2 amplified DNA from all 10 strains of S. intermedia from pigs but from only 4 of 10 strains from chickens, whilst NOX3 amplified DNA from only 18 of 21 S. pilosicoli strains, even at low stringency. Tests NOX1 and NOX4 should prove useful in veterinary diagnostic laboratories, whilst NOX2 and NOX3 require further refinement.

Animals↗
PubMed1999

Analysis of Serpulina hyodysenteriae strain variation and its molecular epidemiology using pulsed-field gel electrophoresis.

Pulsed-field gel electrophoresis (PFGE) was applied as a molecular typing tool for the spirochaete Serpulina hyodysenteriae, the agent of swine dysentery. Analysis of a collection of 40 mainly Australian isolates, previously characterized by other methods, divided these into 23 PFGE types. This confirmed that there are many strains of the spirochaete in Australia. PFGE was more discriminatory for strain typing than both multilocus enzyme electrophoresis and serotyping. It had similar discriminatory power to restriction endonuclease analysis, but the results of PFGE were easier to interpret. When applied to 29 isolates collected from 4 farms over periods of up to 8 years, 2 PFGE patterns were found on 3 farms, and a single pattern on the other. In each case a new strain had apparently emerged as a variant of an original parent strain. PFGE was found to be a powerful technique for investigating the molecular epidemiology of swine dysentery outbreaks.

Animals↗
PubMed1999

Adverse effects of soluble non-starch polysaccharide (guar gum) on piglet growth and experimental colibacillosis immediately after weaning.

This study evaluated the effects of adding soluble fibre to the diet of healthy weaner pigs and weaner pigs experimentally infected with enterotoxigenic Escherichia coli (ETEC) in a model of post-weaning colibacillosis. Bodyweight gain, intestinal changes and proliferation of ETEC were measured 7 days following weaning. The basal diet consisted of pregelatinised rice fortified with animal protein. Addition of guar gum to this diet elevated the soluble fibre content from 1 to 6 per cent, and was associated with reduced bodyweight gains, increased large intestinal weights and fermentation, and increased proliferation of ETEC in the small intestine. The optimal levels and type of dietary fibre used for weaner pig diets require further evaluation.

Animal Feed↗
PubMed1999

Lipo-oligosaccharide profiles of Serpulina pilosicoli strains and their serological cross-reactivities.

The purpose of this study was to determine the presence of lipopolysaccharide-like material in the intestinal spirochaete Serpulina pilosicoli and the extent of antigenic cross-reactivity of this material in different strains of the species. Hot water-phenol, aqueous-phase extracts from five porcine and three human strains of S. pilosicoli, and from seven strains of four other Serpulina spp., were separated by SDS-PAGE and silver-stained profiles were obtained. All S. pilosicoli strains had a predominant band at c. 16 kDa. Some also had a partial ladder-like profile, consistent with the presence of semi-rough lipo-oligosaccharide (LOS); this was more obvious in Western immunoblot analysis. LOS from each S. pilosicoli strain was serologically distinct in immunoblot analysis and there was no cross-reactivity with other Serpulina spp. The serological diversity found amongst the LOS of S. pilosicoli strains may help to explain why individual people and animals can suffer repeated infections with different strains of the organism.

Animals↗